Rapid hardening, ultra-high early strength portland-type cement compositions, novel clinkers and methods for their manufacture which reduce harmful gaseous emissions

ABSTRACT

Clinkered materials containing high concentrations of {(C,K,N,M) 4  (A,F,Mn,P,T,S) 3  Cl,{overscore (S)})}(crystal X), and {C 2 S) 3 (C{overscore (S)}) 3 Ca(f,Cl) 2 } or C 9 S 3 {overscore (S)} 3 Ca(f,cl) 2  crystal Y), and/or {C 5 S 2 {overscore (S)}) (crystal Z) directly from the kiln, rapidly hardening ultra-high early strength cement including these clinkered materials, methods for forming and using said compositions and the cements so produced are claimed. The methods include the steps of forming a mixture of raw material containing CaO, MgO, Al 2 O 3 , Fe 2 O 3 , TiO 2 , Mn 2 O 5 , SiO 2 , SO 3 , Na 2 O, K 2 O, P 2 O 5  and F, respectively designated C, M, A, F, T, Mn, S, {overscore (S)}, N, K, P and f, and heating said mixture to an elevated temperature between 900° C. and 1,200° C.; before determining average amount of crystals X, Y, and Z. Final mixtures comprising these clinkers and hydraulic or portland type cement are made to produce cement compositions having crystal X concentrations of approximately 5% to 35% by weight, crystal Y concentrations of approximately 5% to 40% by weight, and/or crystal Z concentrations of approximately 5% to 40% by weight, with the remainder being hydraulic or portland type cement. The cements so produced are rapid hardening and exhibit high strengths ranging from 2,000 psi to 7,000 psi in one hour, 6,000 to 8,000 psi in one day and 9,000 to 12,000 psi in 28 days. They are sulfate and sea-water attack resistant and have low heats of hydration, minimal shrinkage, and high water impermeability. The methods claimed also results in significant reduction in gaseous emissions including SO x , NO x  and CO x .

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/716,577 filed Nov. 20, 2000 which is a continuation-in-partof U.S. patent application Ser. No. 09/654,288, filed Sep. 1, 2000,which is a continuation of U.S. patent application Ser. No. 09/301,370,filed Apr. 16, 1999, now U.S. Pat. No. 6,113,684, hereby incorporated intheir entirety by this reference.

FIELD OF THE INVENTION

The present invention relates in a broad aspect to rapid hardening highstrength cement compositions and methods for their formation includingthe formation of special clinkered compositions. More particularly, thepresent invention is directed to rapid hardening, high strength cementcompositions and to low emission methods for their formation whichbeneficially utilize the formation of special crystals in the cementclinker to significantly enhance the early compressive strength, sulfateresistance, and water impermeability of the cement.

BACKGROUND OF THE INVENTION

The manufacturing of hydraulic cement dates back to the earliest days ofthe Roman Empire. Pozzolana, a volcanic ash from one of the world'searliest cement kilns, Mount Vesuvius, was mixed with limestone to forma material capable of hardening under water. During the middle ages thisancient Roman art was lost and it was not until the middle of theeighteenth century that natural hydraulic cements were again made byburning mixtures of clay and limestone at high kiln temperatures toproduce a clinker which was mixed with water and allowed to set or cure.However, due to the inherent variability associated with natural clayand limestone the exact composition of these natural cements variedwidely and performance was unpredictable.

The art became a science in the early nineteenth century when JosephAspdin invented a process of carefully proportioning combinations ofcalcium, silicon, iron and aluminum found in local clay and limedeposits and burning these materials at high temperatures. This patentedprocess resulted in portland cement with more consistent performancenamed after the stone quarried on the Isle of Portland off the Britishcoast. Portland type cement is still one of the most commonly usedstructural materials today. In spite of significant advances in thematerial sciences, even today the basic process for making cement hasremained essentially unchanged. Raw materials including limestone, clay,and bauxite are measured and mixed then fired at temperatures in excessof 1500° C. (2700° F.) until a cement “clinker” is formed. The finishedclinker is crushed for use as cement and can be mixed with postproduction ingredients such as gypsum, soluble CaSO₄ anhydride andadditional sources of C₂S, C₃S and C₃A to modify properties. Typically,the latter three come from the addition of conventional portland typecement to the clinker.

For convenience of further description, the following standard cementindustry abbreviations will be utilized to describe the composition offired materials:

H-represents water (H₂O)

C-represents Calcium Oxide (CaO)

A-Aluminum Oxide (Al₂O₃)

F-represents Ferric Oxide (Fe₂O₃)

M-represents Magnesium Oxide (MgO)

S-represents Silicon Oxide (SiO₂)

K-represents Potassium Oxide (K₂O)

N-represents Sodium Oxide (Na₂O)

S-represents Sulfur Trioxide (SO₃)

Mn-represent Manganese Oxide (Mn₂O₅)

P-represent Phosphorous Oxide (P₂O₅)

f-represent fluorine F

cl-represent Chlorine Cl.

Recent advances in our understanding of cement chemistry, the thermaldynamics of cement kiln operation and control, and pioneeringbreakthroughs in structural analyses using x-ray diffractioncrystallography have allowed material scientists and cement manufacturesto overcome and minimize many of the variables and problems inherent incement manufacturing. However, two particularly vexing problems remainto be fully resolved. First, modern commercial cement compositions relyon a mineral composition known as C₃S silicate and its hydration (waterincorporation) rate for early strength. Yet, these compositionsinherently contain high concentrations of non-early strength producingC₂S in their base clinkers which cannot be converted to the moredesirable C₃S. High early strength and rapid setting times relate to thehydration rate of the C₃S. General purpose portland type cement (usuallydesignated ASTM I) typically contains approximately 50% C₃S, 25% C₂S,12% C₃A, 8% C₄AF, 5% C. Thus the total amount of calcium silicates isapproximately 75%, with the predominant silicate being C₃S. Thehydration rate of C₃S and C₂S significantly differ with the C₂Scomponent taking up to one year to fully hydrate. Consequently the C₂Scontributes very little or nothing to the early strength of the cementproduct. This is even further exacerbated if additional C₂S is added tothe clinkered material by supplementation with hydraulic cement duringfinal product formulation. Consequently, the net silicate hydrationrate, and therefore the ultimate rate of strength formation, is limitedby the C₂S hydration rate when the aqueous phase (water) is added.

The second perpetual problem associated with all current cementmanufacturing processes is the terrible burden placed on theenvironment. Cement manufacturing is the single most significant sourceof atmospheric SO_(x) (sulfur oxides) contamination. Further, othernoxious gaseous emissions are exuded by the ton from the reactionconditions within the cement kiln. What is more, great quantities offossil fuels are burned to power these huge kilns and plumes of siliconand aluminum particulates are generated by the mixing, packaging andshipping of the raw materials and final cementuous products. Manycollateral methods have been developed to reduce these pollutants.However, the clinker formation process is still fraught with potentiallydisastrous environmental consequences.

There are four primary properties of cement and its products thatmaterial scientists continually work to improve: high early strengths,rapid setting time, resistance to degradation, and good expansiveness tooffset shrinkage. For example, concrete made from portland cementtogether with sand, gravel or other mineral aggregate, typicallyundergoes shrinkage upon drying. This shrinkage is undesirable in that,among other reasons, it gives rise to cracks which ultimately weaken theset concrete.

Cracking results from excessive shrinking and high heats of hydration inthickly poured structures (cement and water react chemically and produceheat unlike plaster and water which merely dries). The shrinkage ratecan be controlled through increasing the amount of calcium aluminumsulfate in the clinker which expands upon hydration in the presence offree CaO and CaSO₄. Early attempts at reducing cracking and therebyincreasing overall strength and resistance to chemical attack resultedin the so-called “calcium alumino sulfate” cements based upon 3CaO,3Al₂O₃, CaSO₄, abbreviated as either C₃A₃C{overscore (S)} or, preferablyC₄A₃{overscore (S)}. Typically, the primary characteristic of C₄A₃Scements is their expansiveness. Addition of additives such asC₄A₃{overscore (S)} counteracts shrinkage and may or may not producecements having early high strength. Examples of these calcium aluminocements can be found in U.S. Pat. Nos. 3,155,526 (Klein), 3,860,433(Ost) and 4,798,628 (Mills).

Resistance to chemical degradation, water permeability and chlorineattack are qualities that result from improved resistance to crackingand chemical neutralization of reactive species by ingredients withinthe cement matrix. Resistance to sulfate attack is provided by limitingthe C₃A content to less than 5%, or using novel means to eliminate C₃Athrough reactions with C{overscore (S)}.

Excepting the Kunbargi patent discussed below, one consistent element ofthe prior art has been the use of kiln temperatures in excess of 1500°C. This temperature has been believed necessary by those skilled in theart to encourage the production of the desirable stable calcium silicateC₃S. However, these elevated kiln temperatures which have dominated thesintering process since Mount Vesuvius first erupted have not beenwithout detriment. The temperatures traditionally used to reachsintering temperatures within the kiln result in a significant source ofthe primary greenhouse gases released during the calcining of CaCO₃ andthrough the burning of fossil fuels in the kiln. In addition to CO₂,copious amounts of NO_(x), and SO_(x) also emanate from the kiln as thecalcining and sintering processes continue. Furthermore, operatingindustrial kilns within narrow controlled ranges is extremely difficultdue to the lack of precise thermal monitoring equipment that can be usedin the high particulate environment of a cement kiln. Consequently, anyadvance in cement manufacturing material science and chemistry that canimprove the final product's desired properties, reduce the number ofpost production ingredients required, and significantly reduce gaseousemissions would be considered an important advance in cementmanufacturing.

Perhaps the most significant advance in portland type cement design andchemistry is disclosed in the present inventor's U.S. Pat. No. 4,957,556patent (Kunbargi). This patent discloses and claims cement compoundsformed from what was then an entirely new class of clinkered materialswhich for the first time contained high concentrations of C₄A₃{overscore(S)}. At that time, the present inventor was the first to inventassociated methods for enriching clinkers to high concentrations ofC₄A₃{overscore (S)}. Broadly stated, this was achieved by adjusting theratio of reactants in the raw materials and by using x-ray defractionanalysis to carefully control kiln temperature to a narrow and specificrange of relatively high temperatures below 1500° C. In addition, cementcompounds of the Kunbargi '556 patent exhibited increased resistance tosulfate attack due to the concurrent discovery that soluble CaSO₄anhydride would react with residual C₃A in the clinker and exogenous C₃Ssources.

However, though a dramatic improvement over the prior art, this earliercement formulation and production technology still requires the tediousand expensive addition of controlled amounts of soluble CaSO₄ anhydrideand exogenous C₃S to the finished clinker. The exogenous C₃S present inthis hydraulic cement additive also brings with it the undesirable C₂Ssilicate which has a slower hydration rate than would optimally bedesired to produce an extremely fast high strength early setting cement.Consequently, although a significant advance over the prior art, thecement compositions of the '556 patent still utilize post manufacturingsupplementation with two active ingredients and have early strengthqualities which are limited by the slow hydration rates associated withthe C₂S in the hydraulic cement supplement.

In spite of these prior art advances in the production of early settinghigh strength cement, the development of portland type cements havingeven greater compressive strengths and higher rates of strengthdevelopment than those presently available would be of great economicbenefit to the cement and the construction industries. For example, inthe production of pre-cast, pre-stressed, concrete products, acompressive strength on the order of 4000-5000 psi at three hours isoften required. Additionally, in the construction and repair ofhighways, bridges and freeway over-passes many days and even weeks ofcuring time are required before these structures set to sufficientcompressive strengths to support their anticipated loads so that theymay be utilized as designed. The resultant delays cost millions ofdollars annually in increased transportation costs and shipping delayswhile critical transportation corridors are shut down waiting forconcrete to harden. Moreover, in the construction of concrete buildings,where the cement matrix is cast into forms, it is necessary to allowdays of curing time to allow the cement to develop sufficient strengthfor removal of the forms. This delay results in lost revenues forproperty owners and inconvenience and storage costs for industrialtenants. Furthermore, because setting rates of portland type cements canbe affected by temperature, an early setting, ultra-high strength cementwith a lower heat of hydration that would make the production of largecomplex superstructures possible in extremely low ambient temperatureenvironments would be an even greater contribution to the constructionindustry.

However, these and other improvements in cement quality should not bemade at the expense of the environment. Cement manufacturing is anotoriously environmentally unfriendly process. In the past, thebenefits that society has received from cement, mortar and concrete haveconsiderably outweighed the environmental impact. However, a process formaking a superior clinkered material than currently known in the artthat would significantly reduce gaseous emissions of SO_(x), NO_(x) andCO_(x) would represent a tremendous industrial and environmentaladvance.

Accordingly, it is a particular object of the present invention toprovide a rapid hardening high early strength portland-type cementcomposition with an extremely rapid C₂S hydration rate. Whereas the bestcements known in the art can produce compressive strengths within onehour on the order of 3000 psi and on the order of 6000 psi within oneday, the cement compositions of the present invention will producecompressive strengths on the order of 5000-7000 psi within one hour, onthe order of 7000-8000 psi within one day. The resulting cementcompounds will also possess a sulfate resistance of 0.01% at one yearwithout requiring the addition of soluble CaSO₄ to the finished clinker,a water permeability of less than 1 mm in one year, a drying shrinkageof 0.03% at 28 days, a heat of hydration of 70 cal/g at 28 days.

It is a further additional object of the present invention to providemethods for producing rapid hardening high early strength portland-typecement compositions, and compositions so produced, which areparticularly well suited for use in pouring large structures, even incold temperatures. This advantageous quality is derived from a generallylow overall rate of hydration resulting from the present invention,where, unlike the prior art hydration, is concentrated during theinitial plastic phase shortly after hydration. This early rate ofhydration generates considerable heat for a relatively short period oftime. However, according to the teachings of the present invention, thishigh initial heat of hydration is dissipated well prior to final settingof the cement thereby reducing thermal cracking in the finished product.

It is a further additional object of the present invention to providemethods for producing rapid hardening high early strength portland-typecement compositions which achieve early high strength through theadvantageous utilization of combined hydrated ettringite.

It is also an object of the present invention to provide methods forproducing clinkered materials using processes that significantly reducethe environmental damage associated with cement manufacturing. Theseimproved methods will result in a reduction in SO_(x) on the order of98%, a 35% reduction in NO_(x), and a 50% reduction in CO_(x) ascompared with conventional clinkered manufacturing methods. Furthermore,the previously unusable waste product, phosphogypsum, can be consumed byprocesses of the present invention, further reducing environmentalimpact.

It is yet another object of the present invention to provide earlysetting ultra-high early strength cement compositions at reduced costsand with greater manufacturing convenience.

SUMMARY OF THE INVENTION

These and other objects are achieved by the methods and cementcompositions of the present invention which utilize low temperatureburning of specific mixtures of raw materials to produce, in the kiln,special clinkers having high concentrations of{(C,K,N,M)₄(A,F,Mn,P,T,S)₃(Cl,{overscore (S)})}(crystal X), and{(C₂S)₃(C{overscore (S)})₃Ca(f,Cl)₂} or C₉S₃{overscore (S)}₃Ca(f,cl)₂(crystal Y), and/or {C₅S₂{overscore (S)}} (crystal Z) which clinkers aremixed with hydraulic or portland type cement to produce final cementcompositions within the scope and teachings of the present invention.When hydrated, the resulting cement compositions exhibit the desirablephysical properties of extremely high strengths, low heats of hydration,low shrinkage, low water permeability, and sulfate resistancecharacteristics, in unusually short periods of time, and ultimately cureto previously unachievable compressive strengths through the combinedaction of the aqueous phases of crystals X, Y, and/or Z

The table below illustrates the dramatic and surprising increase incompressive strengths available as a result of the present inventionversus previously superior compressive strengths produced in accordancewith the '556 patent.

Compressive Cement Type Age Strength 556 Patent one hour 3,000 psi oneday 6,000 psi twenty-eight days 10,000 psi  Present Invention one hour5,000 psi one day 8,000 psi twenty-eight days 12,000 psi 

In accordance with the teachings of the present invention it wassurprisingly discovered by the present inventor that by carefullycontrolling kiln temperature and by adjusting the ratio of raw materialswithin the kiln, that two new and unexpected crystals would form in thekiln and remain stable in the final clinker. These two new, andunexpected crystals, Y and Z, described above, have never before beenformed in a cement kiln. In general, it is believed that crystals Y andZ are C{overscore (S)}/C₂S complexes that when hydrated release a fresh,highly reactive form of C₂S and C{overscore (S)}. This highly reactiveform of C₂S is extremely rapidly hydrated and was unexpectedly found bythe present inventor to significantly accelerate the hydration rate ofthe C₂S normally found in portland-type hydraulic cement supplements.Consequently, when the clinker of the present invention is supplementedwith hydraulic cement the normal C₂S hydrates at rates comparable toC₃S. This produces an extremely high strength cement faster thanpreviously available in the art. Additionally, the C{overscore (S)}liberated from the hydration of crystals Y and Z also is available toreact with parasitic C₃A typically found in supplemental portland typecements which, in accordance with the teachings of the presentinvention, significantly increases sulfate resistance in the resultingcement compositions.

Another benefit of the present invention is the significant reduction ingaseous emissions achieved by its new sintering technique. The over1500° C. prior art temperatures traditionally used to reach sinteringtemperatures within a cement kiln result in the production of theprimary greenhouse gases released during the calcining of CaCO₃.Furthermore, such extreme prior art temperatures require consumption ofsignificantly more fossil fuels to feed the kiln which in turn resultsin additional gaseous emission releases. However, as a result the lowerkiln temperatures required by the methods of the present invention withthe constant kiln monitoring techniques, a 98% reduction in SO_(x), a35% reduction in NO_(x) and a 50% reduction in CO_(x) can be achieved.An equally unexpected and valuable environmental benefit of the presentinvention is that phosphogypsum, a toxic by product of the fertilizerindustry, can be substituted successfully for gypsum (the primary sourceof C{overscore (S)}) in the production of the cement compositionsdisclosed and claimed. In contrast, phosphogypsum cannot be used inprior art concrete manufacturing processes due to the high Pconcentration.

Another unanticipated and valuable benefit of the present invention isthat the novel cement and clinkered compositions and processes result inreduced manufacturing costs and final product costs. The lower kilntemperatures required to produce these novel clinkers significantlyreduce fossil fuel consumption and corresponding fuel costs whileincreasing nominal kiln output by 35% as compared to the nominal kilnspecification and production rate of portland cement. Consequently, theresulting clinkers can be more economically produced than previousclinkers which can result in dramatically lower costs to the consumer.Furthermore, in accordance with the teachings of the present inventionthe rapid hydration rates associated with crystals Y and Z reduce thequantity of clinker required to produce early setting ultra-highstrength cement compounds. Moreover, crystals Y and Z produced inaccordance with the teachings of the present invention, contribute allof the CaSO₄ required to from the final cementous compounds of thepresent invention. Therefore, these factors combine to create superiorcement products at lower costs, which, as a result, can be manufactured,used and sold more economically than prior art technology and cementproducts.

Broadly speaking, the first step of the exemplary methods for producingrapid hardening high strength cement compositions in accordance with theteachings of the present invention involves the formation of a mixtureof limestone, gypsum or phosphogypsum and bauxite, kaolinite or otherhigh alumina clay and calcium fluoride or any other raw materials thatcontain high concentrations of fluoride, such as alkaline fluoride.These provide the necessary reactants of the present invention, S, A, C,F, M, P, f, and {overscore (S)}. These mixtures preferably have anoverall molar ratio of {overscore (S)}/A+F between approximately 0.25and 0.45, an overall molar ratio of S/A between approximately 0.2 and0.6, an overall molar ratio of f/S between approximately 0.06 and 0.1,an overall molar ratio of N/C between approximately 0.05 and 0.1, anoverall molar ratio of K/C between approximately 0.08 and 0.15, anoverall molar ratio of M/C between approximately 0.03 and 0.05, and anoverall molar ratio of P/A between approximately 0.03 and 0.05.

In contrast to the known, prior art, methods of cement production whichfire their raw material mixtures at temperatures above 1200° C., andmore often above 1500° C., the mixtures produced in accordance with themethods of the present invention are heated to elevated temperaturesbetween 900° C. and 1200° C. for a sufficient period of time to formclinkers having high concentrations of crystals X, Y and/or Z discussedabove. It should be emphasized that heating the mixtures of the presentinvention to temperatures greater than 1200° C. will decompose thedesired crystals. Thus, the methods of the present invention producethese crystal phases in the kiln by burning the clinkers at reducedtemperatures.

Once the clinkers have been formed, the average ratios of X/Y or X/Z orX/Y+Z are determined and final mixtures are formed by combining theclinkers with hydraulic or portland type cement so that the finalmixtures include an X+Y, X+Z, or X+Y+Z content of approximately 15% to55% by weight. The remaining 45-85% by weight being hydraulic orportland cement.

Because of the narrow kiln temperature range used in the presentinvention, between 900° C. and 1200° C. at which temperatures X, Y, andZ are stable in the kiln, the methods of the present invention arebeneficially practiced using modern, state of the art kiln temperaturecontrols. Those skilled in this art will appreciate that contemporarycement kilns do not have temperature controls at the burning zone of thekiln itself. Accordingly, temperature control is preferably carried outwith the present invention utilizing x-ray diffraction techniques toperiodically analyze the clinker for the proper content of X and Yand/or Z to verify the proper temperature. Those skilled in the art willappreciate that other forms of clinker analysis and resultanttemperature control may be utilized, though x-ray diffraction ispreferred.

The cement compositions produced in accordance with the methods of thepresent invention, following hydration, produce rapid hardening highearly strength portland-type cements having compressive strengths on theorder of 5000 psi within one hour, 8000 psi within twenty-four hours and12,000 psi within twenty eight days. Thus, the cement compositions soproduced are particularly well suited for use in concrete constructionwhere low shrinkage, sulfate resistance, water impermeability orreduction in setting time will have economic advantage or otherbenefits. Moreover, the previously unattainable compressive strengthsexhibited by the cement compositions of the present invention providesignificant construction advantages, such as reduction in structure sizeand weight, without corresponding reductions in strength. Additionally,the heat of hydration of the compositions of the present inventionprevents the hydrated cements from freezing in cold temperaturesenabling construction to continue at temperatures below 0° C.

It is well known in the art that cement compositions can be mixed withinert materials to produce final products such as mortar and concrete.The cement compositions of the present invention can be mixed withdifferent ratios of sand to produce mortars of any desired consistency.Similarly, the addition of aggregates such as gravel, together withsand, to the cement compounds of the present invention will result inconcrete suitable for various industrial uses.

Further objects and advantages of the cement compositions produced inaccordance with the teachings of the present invention as well as abetter understanding thereof, will be afforded to those skilled in theart from a consideration of the following detailed explanation ofpreferred exemplary embodiments thereof.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In spite of the long history of cement production and use incorporatingC₄A₃{overscore (S)}, the prior art is devoid of processes whicheffectively produce X and Y and/or Z crystals all together in the cementkiln during the burning process. Typically, the well establishedprocedure for producing portland type cement and variations thereofutilizes a rotary cement kiln heat treatment in excess of 1,500° C. tosinter or clinkerize the raw materials. These high temperatures areutilized because the desirable silicates, C₃S and C₂S, start to form attemperatures around 1,300° C. and are stable above 1,500° C. In contrastto these silicates, crystals X, Y and Z, are not thermodynamicallystable at temperatures above 1,300° C. and actually decompose at suchelevated temperatures. As disclosed and claimed herein, crystals X, Yand Z begin to form at temperatures of approximately 900° C. and becomestable at approximately 1,100° C. Therefore, due to the previouslyunrecognized differences in temperature stability between C₃S/C₂S andcrystals X, Y, and Z, cement and clinkers containing both C₃S and C₂S aswell as X, Y and/or Z have not existed until now.

Accordingly, in contrast to the prior art cement producingmethodologies, the methods and compositions of the present inventionutilize special mixing formulas to design raw material mixes which inthe cement kiln itself produce unique clinkers having highconcentrations of crystals X, Y and/or Z. Further, regardless of theability of the special clinkers so produced to become hydraulic cementupon grinding and hydration, when mixed with portland cement accordingto the teachings of the present invention, these unique clinkers producerapid hardening high early strength portland-type cements havingcompressive strengths following hydration ranging from 5,000 psi in onehour, 8,000 psi in twenty-four hours, and up to 12,000 psi intwenty-eight days. The cements of the present invention also exhibitexceptional sulfate resistance of 0.01% in one year, a waterpermeability of less than 1 mm at one year, a drying shrinkage of 0.03%in 28 days and a heat of hydration of 70 cal/g in 28 days.

Before proceeding further, for purposes of explanation and withoutwishing to be bound to the following proposed theory, it has beendetermined that the methods of the present invention produce uniquecement compositions which, following hydration, incorporate crystals ofettringite and calcium aluminate hydrate and calcium silicate hydrates.It is believed that the needle like crystals of ettringite and calciumaluminate hydrate function to strengthen the hydraulic concretes soproduced by forming networks of reinforcing micro-fibers. These internalthree-dimensional reinforcing fiber matrices combine to produce thepreviously unattainable rapid hardening high early strengthportland-type cement characteristics of the cement compositions of thepresent invention. In contrast, prior art cement compositions have beenunable to produce a clinker with crystal X, Y and/or Z because of theexcessive kiln temperatures required. The combination of crystals X, Yand/or Z produced in accordance with the teachings of the presentinvention, combined with hydraulic cement will produce cements thatcombine ettringite from crystals of (C,M,N,K)₆A₃S aq, C₆(A,f)S₃ aq, andC₆(A,f){overscore (S)}₃·aq, and C₃S aq phases in a single cement. Thoseskilled in the art will appreciate that the foregoing proposedmechanisms for the properties of the cement compositions of the presentinvention are theoretical only and do not limit the scope or content ofthe present invention.

As noted above, the first step in the methods of the present inventionis to produce or formulate special cement clinkers containing highamounts of crystals X, Y and/or Z in the kiln. The raw materials forthese clinkers are those commonly known and used for the production ofordinary portland cement clinkers; namely, high alumina clay or bauxiteor kaolinite, limestone, calcium fluoride and gypsum or phosphogypsum(industrial waste material from phosphate fertilizer processing). Thoseskilled in the art also will appreciate that these raw materials aresources of S, A, C, Mn, T, F, P, N, K, Cl, f, and {overscore (S)}, whichare, respectively SiO₂, Al₂O₃, CaO, Mn₂O₅, TiO₂, Fe₂O₃, P₂O₅, Na₂O, K₂O,Cl, F and SO₃. These raw materials are combined in accordance with theteachings of the present invention such that the mixtures so formed havean overall molar ratio of {overscore (S)}/A+F between approximately 0.25and 0.45, an overall molar ratio of S/A between approximately 0.2 and0.6, an overall molar ratio of f/S between approximately 0.06 and 0.1,an overall molar ratio of N/C between approximately 0.05 and 0.1, anoverall molar ratio of K/C between approximately 0.08 and 0.15, anoverall molar ratio of M/C between approximately 0.03 and 0.05, and anoverall molar ratio of P/A between approximately 0.03 and 0.05.

This raw material design has been optimized based upon the followingtheoretical understanding. First, it is known that small amounts ofimpurities will naturally occur in the raw materials utilized to formthe raw material mixes. The impurities normally encountered includesodium oxide (Na₂O), potassium oxide (K₂O), magnesium oxide (MgO),titanium oxide (TiO₂), manganese oxide (Mn₂O₅), phosphate (P₂O₅), andthe like. However, because of the unique compositions of the rawmaterials mixes of the present invention and because of the associatedmethods, these impurities will be incorporated into desirable crystalsin the kiln.

Additionally, in accordance with the teachings of the present invention,S is going to react with C, A, F, f and {overscore (S)} to form crystalsX, Y and/or Z. Any iron present in the raw materials will most likelysubstitute for the alumina in A, but will not form C₄AF or C₂F as longas the ratio of A/F is greater than 0.64. Any silica present in the rawmaterials will react with the remaining C to form crystals Y or Z at theclinkerization temperatures utilized herein. However, this formation isconcurrent with the formation of crystals X. Moreover, crystals X willbe in equilibrium with crystals Y or Z as long as the ratio of{overscore (S)}/A+F is between approximately 0.25 and 0.45. If the ratioof f/S is approximately less than 0.06, the crystal Z phase will beformed. Conversely, if the ratio exceeds approximately 0.1, crystal Yphase will form. If the ratio is between 0.06 and 0.1, crystal Y and Zwill form in equilibrium with crystal X.

Similarly, impurities such as sodium oxide (N) and potassium oxide (K)will be incorporated in crystal X with the sulfate present in the rawmix composition and the remaining sulfate will react to from crystals Yand/or Z. Any uncombined {overscore (S)} will react with C to formcrystals Y, Z and/or C{overscore (S)} and the remaining C will react tofrom crystals Y and/or Z.

Those skilled in the art will also appreciate that the design of the rawmaterial mix of the present invention can be performed using traditionalchemical analysis techniques of the raw materials utilized. For example,assuming an exemplary raw material mix is formed from Bauxite, limestonegypsum, and calcium fluoride containing S, A, C, Mn, T, F, P, N, K, Cl,f, and {overscore (S)}. the following ratios can be utilized inaccordance with the teachings of the present invention to design theexemplary raw material mix.

The amount of Y=26.5 f

The amount of X=1.995 Al₂O₃+1.63 Fe₂O₃+1.64 Mn₂O₅+0.95 SiO₂+2.27 TiO₂+1.71 P ₂O₅

The amount of sulfate in X=0.26 Al₂O₃+0.17 (Fe₂O₃+Mn₂O₅)+0.15SiO₂+0.33TiO₂+0.19 P₂O₅

The amount of sulfate in Y=8.7 f

The amount of silicate in Y=6.3 f

The amount of calcium in C₄A₃{overscore (S)}=0.73 Al₂O₃+0.47(Fe₂O₃+Mn₂O₅)

The amount of C{overscore (S)}=1.7 [{overscore (S)}−(0.65 Na₂O+0.425K₂O+0.26 Al₂O₃+0.17(Fe₂O₃+Mn₂O₅))]

The amount of C in CS=0.41 CS

The amount of C in C₂S=1.87 S

The total required amount of C=0.55 Al₂O₃+0.35 (Fe₂O₃+Mn₂O₅)+1.87 S+0.7{overscore (S)}−0.45 Na₂O−0.30 K₂O

The total required amount of {overscore (S)}=0.65 Na₂O+0.425 K₂O+0.26Al₂O₃+0.17 (Fe₂O₃+Mn₂O₅)

As noted above, the temperature range where crystals X, Y and Z arestable varies between approximately 900° C. and 1,200° C. Accordingly,the mixture of raw materials produced in accordance with the methods ofthe present invention are heated to an elevated temperature betweenthese relatively narrow limits for a sufficient period of time to formthe special clinker having a high concentration of crystals X, and Yand/or Z. This time period will vary depending upon the composition ofthe mixture of the present invention and as known in the art, the kilnand associated cooler geometry. The resulting concentration of crystal Xwill range between approximately 15% and 75%, of crystal Y between 5%and 50%, and of crystal Z between 5% and 75% by weight.

It should be noted that, unlike conventional oven technology with itsrefined temperature control, the present state of the cement kilntemperature control art does not involve traditionally understoodtemperature controls at the burning zone. Typically, the control of theclinker temperature in the kiln is carried out by wet chemical analysisfor free C (free lime). For example, the design formulas for traditionalportland cement raw materials permit the presence of predeterminedamounts of free C in the clinker. If wet chemical analysis of theclinker determines that the amount of free C is higher than the designamount, the clinker is being under burned and the kiln temperature mustbe raised.

However, such wet chemical methods may not be practically applicable tothe production of clinker having high weight percentages of crystals X,Y and/or Z as taught by the present invention. Wet chemical analysis maybe deceiving in this context because the alumina, clay, bauxite and thelike, contain {overscore (S)} and S. The sulfur and silica will reactwith calcium and alumina in crystals X, Y and/or Z. As a result, wetchemical analysis methods may not indicate which crystal phase iscurrently present in the clinker.

Accordingly, a preferred technique for controlling the elevatedtemperatures of the heat treatment of the present invention utilizesperiodic x-ray diffraction analysis of samples taken from the heatedmixture rather than wet chemistry analysis. As with the prior art wetchemical methods of analysis, the previously described formulas of thepresent invention allow the identification and determination of a designamount of crystals X, Y and/or Z in accordance with the teachings of thepresent invention. By preparing a precalibrated x-ray diffraction curve,as known in the art, but here based upon laboratory reference standardsfor quantitatively analyzing the amount of crystals X, Y, and/or Z, oranalyzing the designed mixture having different percentages of crystalsX, Y, and/or Z present in known reference samples, it becomes possibleto periodically remove samples of the heated mixture from the kiln andto quantitatively analyze these samples for the desired design contentof crystals X, Y, and/or Z. Then, as with traditional wet chemistrymethods for kiln control, the temperature of the heated mixture can beadjusted either up or down to produce the desired combination ofcrystals X, Y and/or Z as designed in the raw material mixes of thepresent invention.

It again should be emphasized that the elevated temperature rangesutilized to produce the clinker containing the desired combinations ofcrystals X, Y and/or Z in accordance with the teachings of the presentinvention are relatively narrow when compared to traditional cementclinkerization temperatures. Accordingly, careful temperature controlthrough x-ray diffraction analysis or some other method of firetemperature control should be practiced in order to produce the stablecombinations of crystals X, Y and/or Z phases in the clinker asdisclosed and claimed herein.

Those skilled in the art will also appreciate that an exemplary x-raydiffraction precalibrated curve can be prepared by conducting a numberof laboratory trial design burns of the desired raw material mixes. Thetrials should include underburning, overburning and burning at thecorrect or desired temperatures. The amount of the designed combinationof crystals X, Y and/or Z in each trial burn can then be quantitativelyanalyzed through x-ray diffraction and compared to ASTM standard curvesfor quantitatively calculating the contents of C₃S and C₂S, C₃A and X, Yand/or Z. During production of the clinker in accordance with thepresent invention, a sample of the heat treated raw material willpreferably be taken from the kiln approximately each one-half hour oreach hour to be analyzed quantitatively by x-ray diffraction. Tofacilitate this analysis an x-ray diffraction machine can be computercalibrated to the preburning trials.

Once the clinker has been properly burned or clinkerized, the next stepin the production of the cement compositions of the present inventioninvolves determining the average amount of the combination of crystalsX, Y and/or Z present in the clinker. Typically, the clinker so producedwill not have cementuous values itself upon grinding. Accordingly, thenext step of the cement forming aspect of the present invention involvesforming a final mixture of the clinker with C containing portland-typecement. The compositions of the final mixtures include an X crystalscontent of approximately 10% to 30% by weight, a Y crystals content ofapproximately 5% to 50% by weight, and a Z crystals content ofapproximately 10% to 60% by weight. Mixing the special clinker of thepresent invention with hydraulic or portland type cement is a preferredtechnique because it incorporates C₃S into the cement by providing freelime and C₃S to the mixture.

In contrast to the prior art methods of cement production utilizingknown stoichiometric reactions of crystals X to produce expansivecrystals (or adding C{overscore (S)} anhydrite or gypsum to the clinker)the final cement compositions of the present invention will haveC{overscore (S)} from the hydration process of crystals Y and/or Z. Themethods of the present invention form final mixtures of the clinkers,which contain combination of crystals X, Y and/or Z, with portlandcement or hydraulic cement containing C₃S and C₂S. The hydrationreactions of these novel cement compositions involves not only thehydration of the normal portland cement component such as C₃S and C₂Scrystal, but also the reaction of the disassociated highly reactivateC₂S component from crystals Y or Z. This disassociation can be enhancedby the addition of active alkali ions such as, without limitation,sodium, potassium, lithium, or preferably, their salts, such ascarbonate, sulfate, borate, citrate, hydrate and the like. Moreover,these salts can be used as accelerators for the cement compositions andconcretes thereafter. Also this disassociation can be enhanced by theaddition of organic acids such as, but not limited to, citric acid,sulphonic acid, glycolic acid, tartaric acid, malic acid, and the like.If desired, these acids can be used as a retarders for the cement andconcretes thereafter.

Those skilled in the art will also appreciate that the design mixes ofthe cement compositions of the present invention can be modified toproduce a wide variety of desirable very early strength characteristics.Additionally, various additives can be incorporated into the cementcompositions to provide additional desirable properties. Similarly, thesetting time of the cement compositions of the present invention can befurthered controlled through the adjustment of the mixing proportions ofthe three main raw material components as well as by modifying thefineness of the cements produced in the grinding mill.

For example, in cold or severe weather conditions, the setting time mayincrease from fifteen minutes to approximately two hours. Thus asuitable accelerator, such as aluminum sulfate or iron sulfate may beincorporated into the cement to increase the rate of cure. In additionto those accelerators previously noted, any chloride accelerator usedfor portland cement can also be used with the cement compositions of thepresent inventions. Additionally, a citric acid, tartaric acid, malicacid, or carbonic acid, retarder may be added to the cement compositionsof the present invention to increase the initial set up time tosomething on the order of two hours. However, it should be appreciatedthat an initial set time of fifteen minutes following hydration is anideal time for mixing the cement with a super plasticizer to reduce thequantity of mixing water or the resultant concrete slump.

It should also be appreciated that concrete compositions from the newcements produced in accordance with the teaching of the presentinvention have very low water-permeability, increased sulfateresistance, and improved non-shrinking characteristics. Moreover, thesecement compositions are also sea water resistant. For increasedresistance to freeze and thaw, however, the addition ofsuper-plasticizer, air entraining agents or silica fume to thesecompositions is recommended. A further understanding of the exemplarycement compositions of the present invention and the associated methodsand clinkers will be afforded to those skilled in the art from thefollowing non-limiting examples:

EXAMPLE I

In accordance with the methods of the present invention an exemplarymixture of limestone, gypsum and Bauxite was produced to form a rawmixture for a clinker containing X and Y crystals. The components of themixture were combined in the form of dry powders. The chemical analysisof the raw materials was as follows:

Bauxite Limestone Gypsum SiO₂ 3.77% 0.97% 1.55% Al₂O₃ 74.93% 0.42% 0.50%CaO 0.23% 53.00% 31.85% Fe₂O₃ 1.23% 0.18% 0.20% MgO 0.12% 1.60% 3.60%K₂O 0.14% 0.15% 0.05% SO₃ 0.50% 0.10% 40.45% TiO₂ 3.78% 0.02 000 L.O.I.14.78% 43.00% 22.75%

Utilizing the raw material mixing formulas of the present invention itwas determined that a clinker containing an average of approximately 75%crystal X and 25% crystal Y could be produced from these raw materialsby mixing 40% by weight of the limestone with 26% by weight of thegypsum and 34% by weight of the bauxite. This raw material mixture wasfired at a temperature between 1,000° C. and 1,200° C., to produce ahigh C₄A₃{overscore (S)} clinker. The clinker so produced did not haveany cementuous values.

The emission gases during the burn were reduced significantly comparedto those of normal portland cement clinker. For instance the emission ofSO₃ during the burning of the clinker of Example I ranged from 13 ppm to82 ppm, compared to the 500 ppm limit for normal portland cementclinker. Those skilled in the art also will appreciate that the lowerburning temperatures of the present invention will reduce NO_(x)emissions by nearly 30%. Further, the lower content of limestone in theclinkers of the present invention as compared to those of portlandcement will lower the emission of CO_(x) by nearly 50%.

Again, using the mixing procedures of the present invention, thisexemplary clinker was further mixed with portland cement in thefollowing proportions: 40% high crystal X and Y clinker, 60% portlandcement type II. The resultant exemplary cement mixture containedapproximately 25% crystal X, approximately 10% crystal Y andapproximately 65% silicate (C₃S and C₂S). A test of this exemplarycement mortar designed to demonstrate compressive strength as a functionof age produced the following results:

Age Compressive Strength 1.5 hours  6,000 psi   3 hours  7,000 psi   1day 10,000 psi   7 days 10,500 psi  28 days 12,000 psi

EXAMPLE II

As with Example I, an initial mixture of raw materials, this timecomprising bauxite, limestone and phosphogypsum (industrial wastematerial from phosphate fertilizer processing), was produced inaccordance with the present invention to form a raw material mixture foruse in producing a combination of X, Y, and Z crystal clinker. Thechemical analysis of the raw materials was as follows:

Bauxite Limestone Phosphogypsum SiO₂ 9.50% 11.00% 5.00% Al₂O₃ 48.00%1.50% 0.20% CaO 4.30% 47.60% 29.60% Fe₂O₃ 27.00% 0.30% 0.13% MgO 0.23%0.30% 0.19% K₂O 0.74% 0.15% 0.05% SO₃ 0.00% 0.10% 41.00% L.O.I. 13.00%40.00% 22.00% TiO₂ 3.50% 0.00% 0.00% P₂O₅ 000 000 0.32% F 000 000 0.165%

Utilizing the mixing formulas and techniques of the present invention,it was determined that after firing these raw materials, a clinker couldbe produced containing 52% crystal X, 15% crystal Y, and 25% crystal Zby combining 28% by weight bauxite with 25% by weight limestone and 47%by weight phosphogypsum. Again, utilizing the teachings of the presentinvention, the fired clinker was combined with portland type I-II cementin the proportions of 50% high combination of X, Y and Z crystalclinker, 50% portland type I-II cement, to produce a final cementcomposition containing 25% crystal X, 7% crystal Y and 13% crystal Z,and 55% C₂S and C₃S.

When hydrated, the exemplary cement composition of Example II, exhibiteda low heat of hydration of 58 Kcal/kg in 3 days and 70 cal/g in 28 days.It also exhibited sulfate resistance of 0.01%, a water permeability ofless than 1 mm, a drying shrinkage of 0.03%, a heat of hydration of 70cal/g.

Those skilled in the art will appreciate that this exemplary heat ofhydration is comparable to the low heat of hydration type of portlandcement. Also, those skilled in the art will appreciate that thisexemplary heat of hydration evolved during the initial plastic stage ofthe hydrated cement and made this exemplary cement compositionparticularly well suited for applications in cold weather and sub-zerotemperatures as well as reducing the potential for heat inducedcracking.

The range of X, Y and/or Z crystal combinations that may be produced inaccordance with the teachings of the present invention in the initialfired clinker can vary widely. However, an X crystal content of lessthan approximately 10%, though being within the scope of the presentinvention, most likely would not be economically desirable. Conversely,depending upon the chemical compositions of the raw materials involvedin producing the original mixtures for the clinkers, an X content ashigh as approximately 75% is contemplated as being within the scope ofthe present invention. The same is true for crystal Y and/or crystal Z,where content of less than approximately 5% is within the scope of thepresent invention, but most likely would not be economically desirable.Conversely, depending upon the chemical composition of the raw materialsinvolved in producing the original mixtures for the clinkers, a crystalY and/or crystal Z content as high as approximately 75% is within thescope of the present invention.

Similarly, mixing ratios for the fired clinkers and portland cementclinker can also vary widely depending upon the desired percentage of X,Y and/or Z crystals in the final cement compositions. However, it isanticipated that the most economical cement compositions produced inaccordance with the present invention will contain a weight percentageof crystal X ranging from approximately 10% to 30%. Accordingly, theassociated content of crystal Y and/or crystal Z will most economicallyvary from approximately 5% to 55%. The remainder of the compositions canbe formed of any type of hydraulic cement. However, it is preferred thatthe added hydraulic cements have a high content of the C₃S phase. Thus,the remainder of the cement compositions will preferably compriseportland type cement varying from approximately 45% to 85% by weight ofC₂S and C₃S, depending upon the desired strength and other properties ofthe intended final hydraulic cement products.

Clinkers made in accordance with the teachings of the present inventionare analyzed using methods known to those skilled in the art ofquantitative analytical inorganic chemistry including, but not limitedto x-ray technology. Using the aforementioned analytical methods theclinkers of the present invention were found to contain between 3 wt.percent to 14 wt. percent SiO₂, between approximately 10 wt. percent to45 wt. percent Al₂O₃, between approximately 1 wt. percent to 9 wt.percent Fe₂O₃, between approximately 38 wt. percent to 57 wt. percentCaO, between approximately 0.2 wt. percent to 2.0 wt. percent MgO andbetween approximately 5 wt. percent to 25 wt. percent SO₃ and betweenapproximately 0.01 wt. percent and approximately 2.25 wt percentFluorine.

It is understood that in cases where the exact concentration of theaforementioned chemical compounds do not total 100 wt. percent that theremainder wt. percent may be composed of one or more chemical speciesdescribed elsewhere in this specification, or different chemical speciesincidentally found in the raw material mix used to prepare the clinkersof the present invention. Moreover, it is understood that the presenceof such chemical species other than those listed in Table III below arenot necessary or required to form the clinkers of the present invention.

The abbreviations SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO and SO₃ are to be giventheir ordinary meaning as known to those skilled in the chemical artsand as described on a standard Periodic Table of the Elements. The term“approximately between” is not intended to add uncertainty or ambiguityto subject matter of the present invention and is merely used to denotethat the wt. percentages stated are not absolutely exact and that minorfluctuations in the ranges consistent with the limits inherent inquantitative analytical methods are within the scope of the invention.

The term “wt. percent” is “weight percent” as defined in standardchemical texts to mean wt. of solute/wt. of solution×100, or used hereinthe weight of the inorganic chemical compound/the weight of the clinkermaterial×100.

TABLE III Clinker Date Weight Percent Number Analyzed SiO₂ A1₂O₃ Fe₂O₃CaO MgO SO₃ F 1 12/95 10-11 14-15 8-9 48-50 1.5 22-23  1.2-2.25 2 12/9711-12 21-22 1-2 40-42 1.3 21-23   1-1.17 3 12/99  5-6 33-34 2-3 38-400.5 19-20 0.01-0.5 4  3/99  4-6 23-25 2-3 48-53 1-2 23-25  0.6-1 5  6/99 5-7 40-45 4-5 48-53 0.2-.05  5-8  0.5-0.7 6 05/00 12-14 10-15 3-4 55-570.5-1  8-10  1.2-1.8 7 06/00  3.5 38-43 2-3 38-41 1-2 11-14  0.5-1

In the foregoing description of the present invention, preferredexemplary embodiments of the invention have been disclosed. It is to beunderstood by those skilled in the art that other equivalent cement andclinker compositions are within the scope of the present invention.Accordingly, the present invention is not limited to the particularexemplary compositions which have been illustrated and described indetail herein.

What is claimed is:
 1. A clinkered material comprising: a crystal havingthe cement industry formal {(C,K,N,M)₄(A,F,Mn,P,T,S)₃(cl,{overscore(S)})} plus at least one other crystal selected from the groupconsisting of {C₉S₃{overscore (S)}₃Ca(f cl)₂} and C₅S₂{overscore (S)}wherein said clinker contains between approximately 3 wt. percent to 14wt. percent SiO₂, between approximately 10 wt. percent to 45 wt. percentAl₂O₃, between approximately 1 wt. percent to 9 wt. percent Fe₂O₃,between approximately 38 wt. percent to 57 wt. percent CaO, betweenapproximately 0.2 wt. percent to 2.0 wt. percent MgO, betweenapproximately 5 wt. percent to 25 wt. percent SO₃ and betweenapproximately 0.01 wt. percent and approximately 2.25 wt percentFluorine.
 2. The clinkered material of claim 1 wherein said wt. percentof SiO₂, is between approximately 4 to 6, said wt. percent of Al₂O₃ isbetween approximately 23 to 25, said wt. percent of Fe₂O₃ is betweenapproximately 2 to 3, said wt. percent of CaO is between approximately48 to 53, said wt. percent of MgO is 1.0 to 2.0, said wt. percent of SO₃is between approximately 23 to 25 and said wt percent of Fluorine isbetween approximately 0.6 to
 1. 3. The clinkered material of claim 1wherein said wt. percent of SiO₂, is between approximately 5 to 7, saidwt. percent of Al₂O₃ is between approximately 40 to 45, said wt. percentof Fe₂O₃ is between approximately 4 to 5, said wt. percent of CaO isbetween approximately 48 to 53, said wt. percent of MgO is 0.2 to 0.5,said wt. percent of SO₃ is between approximately 5 to 8 and said wtpercent of Fluorine is between approximately 0.5 to 0.7.
 4. Theclinkered material of claim 1 wherein said wt. percent of SiO₂, isbetween approximately 12 to 14, said wt. percent of Al₂O₃ is betweenapproximately 10 to 15, said wt. percent of Fe₂O₃ is betweenapproximately 3 to 4, said wt. percent of CaO is between approximately55 to 57, said wt. percent of MgO is 0.5 to 1.0, said wt. percent of SO₃is between approximately 8 to 10 and said wt percent of Fluorine isbetween approximately 1.2 to 1.8.
 5. The clinkered material of claim 1wherein said wt. percent of SiO₂, is between approximately 3 to 5, saidwt. percent of Al₂O₃ is between approximately 38 to 43, said wt. percentof Fe₂O₃ is between approximately 2 to 3, said wt. percent of CaO isbetween approximately 38 to 41, said wt. percent of MgO is 1.0 to 2.0,said wt. percent of SO₃ is between approximately 11 to 14 and said wtpercent of Fluorine is between approximately 0.5 to 1.0.
 6. A concretecomprising a clinkered material according to any one of claim 1, 2, 3, 4or
 5. 7. A very early setting, ultra high strength cement made using theclinker of claim
 1. 8. A very early setting, ultra high strength cementhaving a compressive strength greater than 3,000 psi withinapproximately one hour following hydration comprising a fluoridecontaining clinker having a fluoride content of between approximately0.01 wt. percent to approximately 2.25 wt percent.
 9. The very earlysetting, ultra high strength cement of claim 7 having a compressivestrength greater than 3,000 psi within approximately one hour followinghydration.
 10. A concrete comprising a very early setting, ultra highstrength cement according to any one of claim 7, 8 or 9.